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Why model starts at different carbon value with same land restart file ?

rambhari01

Ram
New Member
Dear CESM Community,

What version of the code are you using?
- using CESSM2.2.2


Describe your problem or question:
I
am starting two different runs using the composets given below.

1850_CAM60_CLM50%BGC_CICE%PRES_DOCN%DOM_MOSART_SGLC_SWAV.

&

FHIST_CAM60_CLM50%BGC_CICE%PRES_DOCN%DOM_MOSART_SGLC_SWAV


The difference between these 2 runs sought to be as first would be 1850 control run with everything to be of 1850 and 2nd is supposed to use the FHIST (as time) so that it can use the historical forcings and we fiexd the CO2 to 1850 only.

Both of these runs use the same initial land restart files as I want to branch these runs form an existing run (same strart point). for this I used the namelist "

finidat = "F1850_CAM6CLM5BGC_NOcrop_CTRL_I3.clm2.r.1910-01-01-00000.nc" " in use_nml_clm for both of these runs.

After running both of these runs for several years, I plotted the carbon stocks for these 2 runs. Everything seems okay but I it can be seen that both of these run start at different total carbon values for these 2. Which is unexpected. Since I am using the above mentioned same restart files file both of these run I expected to start them from the same carbon value.

However, when i was using this restart file for the "FHIST.." compset. initially, model thrown an error and it suggested to use "use_init_interp = .true." in name list variable. When i used this model runs smoothly but I noticed a difference in starting carbon values.

Please help me understanding is it the different time values in compset (1850 and FHIST) has made this difference, how?

Please see the attached plot and see the different start C value s for both of these run (blue and red) instead of using the same land restart files.



Thank you.

-Ram
 

Attachments

  • TOTCOLC_TOTECOSYSC_TOTLITC_TOTSOMC_TOTVEGC_TOTFIRE_ANNUAL_time_series.pdf
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